I can see what they’re trying to accomplish here, but they’re doing it ALL WRONG.
Awfully worded question. Teacher’s Answer was terrible too.
HERE’S HOW I WOULD DO IT:
“If you have 8 and you have 5, can you get to 10?
If so, what happens when you get to 10?
Can you write that in a math formula?
If so, try.”
THAT’S how I would do it, if I was a math teacher who had to teach Common Core.